Engine preservative oils



United States Patent ENGINE PRESERVATIVE 0115 William H. Brugmann, J12, Milltown, Leonard EJMoody, Cranford, and Max W. Hill, Westfield, N. J., 'assigrfors -to- Esso Research and Engineering Company, a corporation of Delaware 7 No Drawing. Application May 27, 1955,

Serial No. 511,788

11 Claims. (Cl. 25233.4)

invention relates to lubricating oils and methods of compounding them. It particularly relates to engine preservative oils having effective anti-rusting properties needed under specialized conditions.

This application is a continuation-in-part of 'copending application S. N. 247,754, filed September 21, 1951, now abandoned.

Engine preservative oils are generally employed as lubricants for new automotive equipment and the like during -'the shipping period and initial breaking-in period. Therefore, such oils must not only meet the requiremerits expected of engine lubricants for conventional use but also must have versatile rust preventive properties to protect the equipment under a wide variety of corrosive influences. For example, new equipment is susceptible to corrosion by inorganic acids such as HBr formed in the combustion of leaded gasolines. 'In addipen, the engine may encounter corrosion by moisture and aqueous solutions of electrolytes such as sea water or 'by various other types of corrosive reagents that may come into contact with the metal parts. The oils should also have good detergency properties and inhibit the corrosion of bearings. Prior art lubricating oil formulations may meet one or two of the rigid requirei'nen'ts imposed upon oils used in such service, but do not possess the versatility required when the oils are used in relatively new engines subjected to rather exmeme "cim'diticms.

it has been found that-an unexpectedly superior lubricant from the standpoint of good engine performance and versatile anti-corrosive properties is obtained by compounding with the oil base stock at least :four different components, each component cooperating in "eliminating or minimizing undesirable characteristics of the oil. These components include an oil-soluble metal salt of an alkylated phenol sulfide, both an alkaline earth metal and an alkali metal oil-soluble petroleum sulfomate, and an oil-soluble aliphatic alcohol. All of these components must be .present in the composition to at tain the desired degree of protection against corrosion and to provide an oil having the desired detergency characteristics. .It is usually desirable to add to the 'oil a bearing corrosion inhibitor such as "PxSy treated terpene's, sulfuri'zed terpenes, thiocarbamates, phenothiazines, Xanthates, etc.

The'oil-soluble metal salts .of the alkyl phenol sulfides useful'in the present invention are well known as being effective detergents and sludge dispersers for lubrieating oils. Oil-soluble compounds of the phenol sulfide with metals such as sodium, potassium, aluminum, tin, zinc, cobalt, nickel, barium and the like may be used. The preparation of calcium salts of this type and their use in lubricants is disclosed in Mikeska patlent, U. 8. 2,362,289. The preparation of barium salts -andmixefi alkaline earth salts containing two different 2,758,972 Patented Aug. 14, 1956 alkaline earth metals are described and claimed in U. S. 2,480,664 to McNab, 'McNulty and Cross.

The alkaline earth metals including calcium, barium, and strontium, are the preferred metals. The presence of at least one alkyl group on the benzene nucleus is desired to impart oil solubility to the composition, the alkyl group containing from about 4 to 12, preferably about 6 to 9, carbon atoms. The alkyl group may :be straight or branched chain and includes, for example, such alkyl groups as amyl, hexyl, 'heptyl, iso-octyl, ten;-

'octyl, nonyl (a polyethylene timer), decyl, 'lauryl, etc.

Although the invention is not limited to compounds having a definite number of sulfur atoms interconnecting benzene nuclei, compounds containing from 1 to 4 sulfur atoms are preferred. The salts may contain an equivalent of about one mol of metal .for 'each '.pair

of phenol radicals in the compound or may contain up to one mol of metal per phenol radical to form basic, high metal-content salts.

The term oil-soluble metal salt of the alkyl phenol sulfide" as used herein refers broadly to the single and mixed salts of the various phenol sulfides, as well as to the basic "form of these sulfides. As a general rule, the phenol sulfide is added to the composition of -the present invention in amounts ranging from about 0.4 to 5% by weight, preferablyffrom '015 "to 1.0% by weight, of the total composition. Percentages of [from 0.6 to 0. 91% by weight "have been found to be particularly advantageous.

The oil-soluble petroleum sulfonates used in the present invention are the salts of oil-soluble or so-called sulfonates are preferably the calcium salts although'the magesium, strontium and other alkaline earth metals may be employed. Particularly advantageous also are alkaline earth metal petroleum sulfonates having an excess rather than a stoichiometric amount of polyvalent metal salt added to the sulfonic acid in the preparation step. Such *sulfonates may be prepared "by the procedure described in U. S. 2,467,176 to Zimmer, Carlson and Duncan.

Such sulfonates may be referred to as basic alkaline earth metal oil-soluble petroleum sulfonates. "The term oil-soluble, alkaline earth metal petroleum 'sulfonates as used in the present specification and claims refers to both of the above general types of alkaline earth metal sulfonates. The alkaline earth metal sulfonates may vary in molecular weight from about 750 to as high as 1100, although preferably the molecular weight range is from about 800 to 1000. Each type of 'sulfonate is used in the finished composition in amounts ranging from about 0.4 to 10 wt. percent, but preferably in the range of 0.4 to 1 Wt. percent. Percentages of 0.45 to 0.87 wt. percent alkali metal sulfonate and 0.52 to 0176 Wt. fpercent alkaline earth metal sulfonate have been found to be particularly advantageous. The weight ratio of alkaline earth to alkali metal sulfonate is maintained in the range of about 0.4:1 to :3: 1, preferably about 0.6:1 to 1.7 :l.

The' high molecular weight aliphatic alcohols used in the practice of the present invention should be soluble in-low concentrations in the lubricant. The should have at least 7 carbon atoms and preferably no more than 20 carbon 'atoms. Those having from about 8 to 18 carbon atoms "are generally preferred. The saturated straight or branched chain aliphatic alcohols such as octyl, lauryl, cetyl, stearyl, and the like, may be used.

The corresponding olefinic alcohols such as oleyl and the like are also suitable. Mixed naturally occurring alcohols such as the Lorols (coconut oil alcohols, Ca to C18, average about C12), wool fat which contains substantial amounts of alcohols having 16 to 18 carbon atoms, sperm oil containing a high percentage of cetyl alcohol, and the like maybe used. The aliphatic alcohols prepared synthetically by various chemical processes are suitable such as, for example, alcohols produced by oxidation of petroleum hydrocarbons such as paraffin wax, petrolatum and the like which occur in the proper molecular weight range. Particularly advantageous are the alcohols produced by oxonation of olefins, such as polymers and copolymers of propylene and butylenes, with carbon monoxide and hydrogen by the well known x0 process. Such alcohols, known as Oxo alcohols, are generally branched chain, saturated aliphatic alcohols. Mixtures of two or more of the above alcohols may be used.

Although thealcohols, when used alone in the oil, are generally quite ineifective for inhibiting metal corrosion by inorganic acids, they are surprisingly eflective for this purpose when used in combination with the other ingredients. Corrosion inhibiting amounts of the alcohols are generally rather low. About 0.3 to'2.0 wt. per cent, preferably aboutv 0.4 to 1.5 Wt. per cent, of the alcohol is used in the present compositions. The alcohol may be added up to the limit of its solubility in the oil in some cases, but preferably no more than about 2.5 to 3% by weight will be added to the finished composition. The effectiveness of the alcohol used for preventing rusting will vary with its molecular weight, and higher concentrations of high molecular weight alcohols will usually be required than is the case with lower molecular weight alcohols.

alcohol to weight per cent concentration of alcohol in the blend be about 9 to 20, preferably about 9 to 17.

In the range of 0.2 to 2.0 wt. per cent of'a sulfurbearing compound, such as an alkyl thiuram disulfide,

EXAMPLE I A series of blends was prepared employing an SAE 30-grade motor oil base stock derived from a solvent extracted, Mid-Continent crude fraction compounded It is generally preferred that Y the ratio of average number of carbon atoms in the ium). The calcium petroleum sulfonate used in the blends had an average molecular weight of about 950. The sodium petroleum sulfonate used in the blends had an average molecular weight of about 480. Cs branchedchain, aliphatic alcohols, prepared by the catalytic ox onation of C7 olefins with carbon monoxide and hydrogen, were used. In addition, the blends in' some cases contained sulfurized dipentene and butyl thiuram disulfide as bearing corrosion inhibitors.

The blends were subjected to various corrosion tests. Humidity cabinet life was determined by coating standard steel panels with the blend and placing the panels in a cabinet maintained at a temperature of 100 F., and a relative humidity of 100%. The time in hours required to rust the panels in the cabinet is termed the humidity cabinet life. This test gives a measure of the protection afforded metal surfaces by the engine preservative oils when equipment is used in humid atmosphere.

The blends were tested bythe so-called sea water corrosion test which is a measure of the extentto which metal surfaces are protected from corrosion by sea water spray when using various preservative oils. In this test, three metal test panels were immersed in the test oil for one minute, and the panels then were suspended in air for 20 hours at room temperature (77 F.). The panels were then suspended in a standard synthetic sea water solution containing various inorganic salts for 20 hours at room temperature. The panels were then cleaned and rated. To pass the test, at least one of the panels must be absolutely free from corrosion and at least one of the other panels must have no more than three small corroded spots. Otherwise, the oil is rated as failing the test.

The blends were also subjected to the I-IBr corrosion test which indicates theprotection afforded metal surfaces by the oils against inorganic acids such as HBr formed in engines by combustion of gasolinescontaining tetraethyl lead and a lead scavenging agent (usually a bromo-organic compound). Two metal test panels were immersed in an 0.1 wt. per cent aqueous solution of hydrobromic acid for one second. The panels were then immersed in and removed from the test oil a total of 12 times during a period of one minute and then suspended in the air for 4 hours at room temperature. They were then cleaned and rated for corrosion. For an oil to pass the test, one of the panels must be absolutely free of corrosion and the other must have no more than three small corroded spots.

The results of the tests are shown in Table I below:

Table I.-Additives used in SAE 30 base stock Barium Sulfurized tert.-octyl Ga sulf. Na suit. Wt. ratio 08 alcohol dipentene Humidity Sea water 1131' cert. Blend No. phenol sul- (wt. per- (wt. per- 0a to Na (wt. per- (wt. percabinet corr. 'te

fide (wt. cent) cent) sulfonate cent) cent) life (hrs.) percent) I 1 0. 6 1. 37 1 0. 62 1.37 2 0. 62 0. 5 1325 1. 37 5 0. 62 1. 0 0. 62 1. 37 1 0.62 0. 6 1 0. 83 3 0.76 0. 43 1.77 1 0. 83 3 0. 76 0. 43 1. 77 O. 6 0.81 0.75 0.45 1.67 0 6 1 0. 3 0. 76 0. 73 1. 04 O. 3 1 O. 60 3 0. 76 O. 73 1. 04' 4 0. 6 0. 3 1 0. 91 0. 52 0. 87 0. 60 0. 4 5 0. 24

1 Basic barium tertroctyl phenol sulfide.

1 Calcium sulfonate (5.0 wt. percent calcium).

3 Basic Ca sulfonates (6.5 wt. percent calcium). 4 Ratio of 'No. of O atoms in alcoh 01 to wt. percent cone. of alcohol-about 13.

5 Butyl thiuram disulfide used instead of sulturized dipentene.

with various combinations of additives. The alkaline earth metal salt of the alkyl phenol sulfide used inthe blends was either barium tert.-octyl phenol sulfide .(containing 21.7 wt. per cent barium) or basic barium cert.- octyl phenol sulfide (containing 30.1 wt. per cent barhumidity cabinet life (blends c, D, and F). None of these blends, however, passed the HBr corrosion test. When C3 alcohols were added =to a blend containing barium tert.-octyl phenol sulfide and calcium sulfonate, the final blend had a low humiditycabinet life, 'but'p-a'ssed the HBr corrosion test '(blend B). When Ca alcohols were added to blends containing barium tert-.-octyl phenol sulfide, calcium sulfonate, and sodium sulfonate, the final blend had a high humidity cabinet life and passed both the sea water-corrosionand HBr corrosion tests. The addition of a bearing corrosion inhibitor such as sulfurized dipentene made :no :significant difference -in improving the oil from the standpoint-of either humidity cabinet life or HBr corrosion'tests.

It-is, therefore, seen from the results obtained on the above blends that both an alkaline earth and-an alkali metal petroleum sulfonate 'must'be present in the finished blendto obtaina satisfactory humidity cabinet life. Both a Esaltzof .an-alkyl1phenol sulfide and an .alkaline'earth metal petroleum 'sulfonate .must be used in the blend to obtain desired detergenoy characteristics. The .presence of analcohol along with the 'othercomponents was found 'to beessential 'to impart the desired degree of protection to the oil against corrosion by acids suchas HBr.

"EXAMPLE -II Blend K from Example I was also evaluated in a Lauson engine to determine its bearing corrosion inhibition and detergency properties. A sample of the SAE 30 grade .oil per se was tested for purposes of comparison. The tests were-conductedfor'25 hour periods, the engine beingoperatedat '1800sR. P. M. with a .15 indicated kilowatt-load, 300 Roiltemperature and 295 F. water jacket temperature. 'The oils were then rated on'a demerit system wherein aperfec'tly'cleansurface is given a rating of 0, While a rating of 10 is given the worst condition that can be expected of that surface. The loss in weight of the copper-lead bearings during the test was determined. Results are shown below:

Piston Bearing Lubricant varnish Weight loss,

demerit (mgs./

bearing) SAE 30 oil 5. 50 100 Blend K 0. 88 16 The detergency and bearing corrosion properties of blend K are seen to be quite satisfactory.

EXAMPLE III Alcohol used in blend Ratio, No. of O atoms Blend in alcohol HBr corr.

No. Ooncentrato alcohol test Type tion, Wt. cone.

percent L C1; 0210" alcohol 0. 6 21 Fail. M do 1. 13 Pass. N 0.6 28 Fail. 0 o 1. 0 17 Pass. P Lorol B alcohols 1. 0 13 Borderline. Q do 1. 5 9 Pass.

1 Branched chain alcohols prepared by conventional catalytic oxonation of C12 polymer (trom low molecular weight olefins) with CO and H7,

2 OXD'CIX alcohols, average about 012.: alcohols.

Higher concentrations of the high molecular weight alcohols- (C12C2o) -are generallyrequired topreVentruSting than is required in the case of lower molecular weight alcohols.

The lubricatingoil' base stocks-used in the-compositions of this invention may be straight =mineral lubricating 'oils or distillates derived from various :crudes, or various blended-oils maybe employed as well as derasphalteil residuals. The oils may be refined by conventional methods such as by clay treating, solvent extractiongand the like. Hydrogenated oils or white oils may-also be used. Synthetic oils prepared bythe polymerization of olefins, by the reaction of oxides of carbon with hydrogen, or by'the 'hydrogenationiof coal-or its products m-ay be employed. Certain-animal, vegetable or"fish:oils or their hydrogenated products may be employed, either alone or in a mixture with mineral .oils. The ester--and ether-type synthetic lubricants may also be employed advantageously.

.Examples of other :operable synthetic oilsincludefether alcohols such as those corresponding to the general formula wherein R is an alkyl group, 'forexampla'butyl, n is "an integer from '1 to '5, and xis an integer greater than 1; esters'of monobasic carboxylicacids totaling '20 to carbon atoms, such as those "C4 to C18 aliphtic acids with C4 to C18 aliphatic alcoholsythecito C13 radicals including the butyl, isobutyl, hexyl, octyl, Iiso-octyl, 2- ethyl hexyl, 'nonyl, -decyl, lauryl, 'stearyl and similar radicals; diesters of'dib'asic 'acidssuch'as adipic or seba'cic aidswithmonohydric alcohols such as hexyl, octyl, 2- ethyl hexyl or higher alcohols; esters "of polyethylene glycols' with "Ca to C18 branched "chain 'carboxylic "acids; complex esters of polybasic carboxylic acids, polyhydric alcohols, monobasic acids and/or monohydric alcohols, such as the well known glycol-centered or dibasic acidcentered complex esters; phosphoric acid esters or thioesters of aliphatic alcohols or mercaptans of up to 18 carbon atoms; halocarbon oils such as the polymers of chlorofluoro alkylenes like chlorotrifluoroethylene; organo-siloxanes; sulfide esters; organic carbonates; mercaptals; formals; etc.

The lubricating oils may vary considerably in viscosity and other properties, depending on the particular use for which they are desired, but they will usually range from about 35 to seconds Saybolt Universal viscosity at 210 F. In preparing the compositions of the invention major proportions constituting from about 70 to 98.5 wt. per cent, preferably about 85 to 97 wt. per cent, of mineral and/ or synthetic lubricating oils are employed.

It is also within the scope of the present invention to add other agents as may be needed. Such additives include dyes, pour point depressors, heat thickened fatty oils, sludge dispersers, antioxidants, viscosity index improvers, oiliness agents, anti-wear agents and the like.

What is claimed is:

1. A composition of matter consisting essentially of a major proportion of a lubricating oil, from 0.5 to 1.0 wt. per cent of basic barium tert.-octyl phenol sulfide, 0.4 to 1.0 wt. per cent of basic calcium petroleum sulfonate, 0.4 to 1.0 wt. per cent of sodium petroleum sulfonate, and 0.3 to 2.0 wt. per cent of an aliphatic alcohol containing from 7 to 20 carbon atoms per molecule and a ratio of the number of carbon atoms in said alcohol to the weight per cent concentration of said alcohol in the range of about 9 to 20.

2. The composition of matter of claim 1 wherein said aliphatc alcohol contains from 8 to 18 carbon atoms per molecule and said ratio of the number of carbon atoms in said alcohol to the weight per cent concentration of said alcohol is in the range of about 9 to 17.

3. The composition of matter of claim 1 which includes a corrosion inhibiting amount of a sulfur-containing compound selected fromthe group consisting of sulfurized dipentene and butyl thiuram disulfide.

4. The composition of matter of claim 1 wherein said lubricating oil is a mineral lubricating oil.

5. An engine preservative oil consisting essentially of a major proportion of a mineral lubricating oil, 0.6 to 0.91 wt. per cent of basic barium tert.-octyl phenol sulfide, 0.52 to 076 wt. per cent of basic calcium petroleum sulfonate, 0.45 to 0.87 wt. per cent of sodium petroleum sulfonate, and 0.4 to 1.5 wt. per cent of an aliphatic alcohol containing from 8 to 18 carbon atoms per mole cule and a ratio of the'number of carbon atoms in said alcohol to the weight per cent concentration of said alcohol in the range of about 9 to 17.

6. The engine preservative oil of'claim 5 wherein said aliphatic alcohol is a branched chain, saturated aliphatic alcohol.

7. The engine preservative oil of claim 5 wherein said aliphatic alcohol is a straight chain, saturated aliphatic alcohol.

8. An engine preservative oil consisting essentially of a major proportion of a mineral lubricating oil, 0.81 wt. per cent basic barium tert.-octyl phenol sulfide, 0.75 wt. per cent of basic calcium petroleum sulfonate, 0.45 wt. per cent of sodium petroleum sulfonate and 0.6 to 1.5 wt. per cent of an aliphatic alcohol containing from 8 to 18 carbon atoms per molecule and a ratio of the number of carbon atoms in said alcohol to the weight per cent concentration of said alcohol in the range of about 9 to 17.

9. An engine preservative oil consisting essentially of a major proportion of a mineral lubricating oil, 0.6 wt. per cent of basic barium tert.-octyl phenol sulfide, 0.76 wt. per cent of basic calcium petroleum sulfonate, 0.73

wt. per cent of sodium petroleum sulfonate, 0.6 wt. per cent of a branched chain saturated aliphatic alcohol con-' taining 8 carbon atoms per molecule and 0.3 wt. per cent of 'sulfurized dipentene.

10. An engine preservative oil consisting essentially of a major proportion of a mineral lubricating oil, 0.91 wt. per cent of basic barium tert.-octyl phenol sulfide, 0.52 Wt. per cent of basic calcium petroleum sulfonate, 0.87 wt. per cent of sodium petroleum sulfonate, 0.4 wt; per cent of a branched chain saturated aliphatic alcohol containing 8 carbon atoms per molecule and 0.24 Wt. per cent of butyl thiuram disulfide.

11. A composition of matter comprising essentially a major proportion of a lubricating oil, from 0.5 to 1.0 wt; per cent of a basic alkaline earth metal alkyl phenol sulfide, said alkyl group containing from about 4 to 12 carbon atoms, 0.4 to 1.0 wt. per cent of basic calcium.

petroleum sulfonate, 0.4 to 1.0 wt. per cent of sodium petroleum sulfonate, and 0.3 to 2.0 wt. per cent of an aliphatic alcohol containing from 7 to 20 carbon atoms per molecule and a ratio of the number of carbon atoms in said alcohol to the weight per cent concentration of said alcohol in the range of about 9 to 20.

References Cited in the file of this patent UNITED STATES PATENTS 2,409,726 Winning Oct. 22, 1946 2,412,633 Schwartz Dec. 17, 1946 2,412,634 Schwartz Dec. 17, 1946 2,418,894 McNab et al. Apr. 15, 1946 2,560,202 Zimmer et al. July 10, 1951 FOREIGN PATENTS 715,407 Great Britain Sept. 15, 1954 

1. A COMPOSITION OF MATTER CONSISTING ESSENTIALLY OF A MAJOR PROPORTION OF A LUBRICATING OIL, FROM 0.5 TO 1.0 WT. PER CENT OF BASIC BARIUM TERT-OCTYL PHENOL SULFIDE, 0.4 TO 1.0 WT. PER CENT OF BASIC CALCIUM PETROLEUM SULFONATE, 0.4 TO 1.0 WT. PER CENT OF SODIUM PETROLEUM SULFONATE, AND 0.3 TO 2.0 WT PER CENT OF AN ALIPHATIC ALCOHOL CONTAINING FROM 7 TO 20 CARBON ATOMS PER MOLECULE AND A RATIO OF THE NUMBER OF CARBON ATOMS IN SAID ALCOHOL TO THE WEIGHT PER CENT CONCENTRATION OF SAID ALCOHOL IN THE RANGE OF ABOUT 9 TO
 20. 